qemu/scripts/qtest.py
Alberto Garcia a5df73baaf qtest.py: Wait for the result of qtest commands
The cmd() method of the QEMUQtestProtocol class sends a qtest command
to QEMU but doesn't wait for the return message ("OK", "FAIL", "ERR").
Because of this, it can return control to the caller before the
command has actually finished.

In cases like clock_step or clock_set this means that cmd() can return
before all the timers triggered by the clock change have been fired.
This can be fixed by making cmd() wait for the output of the qtest
command.

This fixes iotests 093 and 136, which are flaky since commit
8258292e18 when the machine is under heavy workload.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2019-02-01 13:46:45 +01:00

116 lines
3.3 KiB
Python

# QEMU qtest library
#
# Copyright (C) 2015 Red Hat Inc.
#
# Authors:
# Fam Zheng <famz@redhat.com>
#
# This work is licensed under the terms of the GNU GPL, version 2. See
# the COPYING file in the top-level directory.
#
# Based on qmp.py.
#
import socket
import os
import qemu
class QEMUQtestProtocol(object):
def __init__(self, address, server=False):
"""
Create a QEMUQtestProtocol object.
@param address: QEMU address, can be either a unix socket path (string)
or a tuple in the form ( address, port ) for a TCP
connection
@param server: server mode, listens on the socket (bool)
@raise socket.error on socket connection errors
@note No connection is established, this is done by the connect() or
accept() methods
"""
self._address = address
self._sock = self._get_sock()
self._sockfile = None
if server:
self._sock.bind(self._address)
self._sock.listen(1)
def _get_sock(self):
if isinstance(self._address, tuple):
family = socket.AF_INET
else:
family = socket.AF_UNIX
return socket.socket(family, socket.SOCK_STREAM)
def connect(self):
"""
Connect to the qtest socket.
@raise socket.error on socket connection errors
"""
self._sock.connect(self._address)
self._sockfile = self._sock.makefile()
def accept(self):
"""
Await connection from QEMU.
@raise socket.error on socket connection errors
"""
self._sock, _ = self._sock.accept()
self._sockfile = self._sock.makefile()
def cmd(self, qtest_cmd):
"""
Send a qtest command on the wire.
@param qtest_cmd: qtest command text to be sent
"""
self._sock.sendall((qtest_cmd + "\n").encode('utf-8'))
resp = self._sockfile.readline()
return resp
def close(self):
self._sock.close()
self._sockfile.close()
def settimeout(self, timeout):
self._sock.settimeout(timeout)
class QEMUQtestMachine(qemu.QEMUMachine):
'''A QEMU VM'''
def __init__(self, binary, args=None, name=None, test_dir="/var/tmp",
socket_scm_helper=None):
if name is None:
name = "qemu-%d" % os.getpid()
super(QEMUQtestMachine,
self).__init__(binary, args, name=name, test_dir=test_dir,
socket_scm_helper=socket_scm_helper)
self._qtest = None
self._qtest_path = os.path.join(test_dir, name + "-qtest.sock")
def _base_args(self):
args = super(QEMUQtestMachine, self)._base_args()
args.extend(['-qtest', 'unix:path=' + self._qtest_path,
'-machine', 'accel=qtest'])
return args
def _pre_launch(self):
super(QEMUQtestMachine, self)._pre_launch()
self._qtest = QEMUQtestProtocol(self._qtest_path, server=True)
def _post_launch(self):
super(QEMUQtestMachine, self)._post_launch()
self._qtest.accept()
def _post_shutdown(self):
super(QEMUQtestMachine, self)._post_shutdown()
self._remove_if_exists(self._qtest_path)
def qtest(self, cmd):
'''Send a qtest command to guest'''
return self._qtest.cmd(cmd)